Compliant electrical contact assembly

ABSTRACT

A compliant electrical contact assembly for temporarily interfacing two electrical devices. The assembly includes a contact having loops with axes forming with a closed coil with opposed contact points. The axes is angled from the direction of the compression force holding the assembly sandwiched between the electrical devices. The electrically shorted loops of the coil slide on the surfaces of one another as the compression force is applied, providing compliance. The contact can be made extremely small such that pitches in the micrometer range can be achieved with very low inductance values. The contact is installed in a through aperture in a dielectric panel such that the contact points extend from opposed openings of the aperture. Optionally, the aperture is filled with a compliant, conductive elastomer.

CROSS-REFERENCES TO RELATED APPLICATIONS

The present application is a continuation-in-part application ofapplication Ser. No. 10/834,727, dated Apr. 29, 2004 for COMPLIANTELECTRICAL CONTACT ASSEMBLY in the name of Gordon A. Vinther, now U.S.Pat. No. 6,909,056, which is a continuation-in-part of application No.10/341,723, dated Jan. 14, 2003 for COMPLIANT ELECTRICAL CONTACT in thename of Gordon A. Vinther, now U.S. Pat. No. 6,787,709, which claimsbenefit of U.S. Provisional Patent Application No. 60/349,850, datedJan. 17, 2002, for SKEWED COIL ELECTRICAL CONTACT, in the name of GordonA. Vinther, and U.S. Provisional Patent Application No. 60/349,852,dated Jan. 17, 2002, for TANGLED WIRE ELECTRICAL CONTACT, in the name ofGordon A. Vinther.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not Applicable

REFERENCE TO A SEQUENCE LISTING, A TABLE, OR A COMPUTER PROGRAM LISTINGCOMPACT DISK APPENDIX

Not Applicable

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to electrical contacts, more particularly,to very small compliant electrical contacts with very low inductance athigh frequencies.

2. Description of the Related Art

The purpose of an electrical contact is to provide a separableelectrical interconnection between two electrical conductors. Thecharacteristic of separability means that the conductors are notinterconnected by permanent mechanical means, such as soldering orbonding, but by temporary mechanical means. Consequently, in order tomaintain a good mechanical contact in an attempt to minimize detrimentalelectrical effects of the contact, some form of spring force is used topress the two conductors together. These electrical contacts are calledcompliant (as in “flexible”) contacts.

Small compliant contacts are necessary for separably interconnectingintegrated circuit (IC) devices to whatever electrical device the userdesires. A prime example is connecting the IC to a test fixture orsorting equipment used for testing and sorting IC's during manufacture.The compliant contact should be as close to electrically transparent aspossible in order to minimize parasitic effects, such as inductance,that alter the signals to and from the IC which could lead to erroneousresults.

Compliant contacts provide another advantage in that they can compensatefor noncoplanarities of the electronic unit under test (UUT) beingconnected. The conduction points on the UUT are not exactly coplanar,that is, they are not within the same plane, even between the sameconduction point on different UUT's. The compliant contacts deflect bydifferent amounts depending upon the actual position of the conductionpoint.

Conventional compliant contacts for connecting to UUT's include springprobes, conductive rubber, compliant beam contacts, and bunched up wirecalled fuzz buttons. Each technology provides the necessary means toovercome the noncoplanarities between the contact points and providesuniform electrical contact throughout a plurality of contacts. Eachtechnology has shortcomings in one characteristic or another and allhave high electrical parasitic characteristics. In addition, they arerelatively expensive to manufacture.

A typical spring probe consists of at least three or four parts, ahollow barrel with a spring and one or two plungers. The spring ishoused in the barrel with the end of the plungers crimped in opposedopen ends of the barrel at the ends of the spring. The spring biases theplungers outwardly, thereby providing a spring force to the tip of theplungers. Spring probes can have highly varying degrees of complianceand contact force, and are generally very reliable for making contactmany times or for many cycles. Spring probes can accommodate manydifferent conduction interfaces, such as pads, columns, balls, etc.Spring probes, however, have a size problem in that the spring itselfcannot be made very small, otherwise consistent spring force fromcontact to contact cannot be maintained. Thus, spring probes arerelatively large, leading to an unacceptably large inductance when usedfor electrical signals at higher frequencies. Additionally, springprobes are relatively costly since the three components must bemanufactured separately and then assembled.

Conductive rubber contacts are made of rubber and silicones of varyingtypes with embedded conductive metal elements. These contact solutionsusually are less inductive than spring probes, but have less complianceand are capable of fewer duty cycles than spring probes. The conductiverubber works when the conduction point is elevated off the UUT thusrequiring a protruding feature from the UUT or the addition of a thirdconductive element to the system to act as a protruding member. Thisthird member lessens the contact area for a given contact force and thusincreases the force per unit area so that consistent contact can bemade. The third element may be a screw machined button which rests onthe rubber between the conduction point. This third element can only addinductance to the contact system.

Compliant beam contacts are made of a conductive material formed suchthat deflection and contact force is attained at one end to the UUTconduction point while the other end remains fixed to the otherconductor. In other words, the force is provided by one or moreelectrically conductive leaf springs. These contacts vary greatly inshape and application. Some compliant beam contacts are small enough tobe used effectively with IC's. Some compliant beam contacts use anothercompliant material, such as rubber, to add to the compliance or contactforce to the beam contact point. These later types tend to be smallerthan traditional compliant beam contacts and thus have less inductanceand are better suited for sorting higher frequency devices. However,these contacts still tend to be somewhat too large to be useful in someradio frequency (RF) applications.

Fuzz buttons are a relatively old yet simple technology in which a wireis crumpled into a cylindrical shape. The resulting shape looks verymuch like tiny cylinder made of steel wool. When the cylinder is placedwithin a hole in a sheet of nonconductive material, it acts like aspring that is continuously electrically shorted. It provides a lessinductive electrical path than other contact technologies. Like rubbercontacts, the fuzz button is most commonly used with a third elementneeded to reach inside the hole of the nonconductive sheet to makecontact with the fuzz button. This third element increases parasiticinductance, degrading the signals to and from the UUT.

IC packaging technology is evolving toward being smaller, higherfrequency (faster), and cheaper, resulting in new requirements for thesetypes of electrical contacts. They need to perform adequately at thelowest cost.

BRIEF SUMMARY OF THE INVENTION

An object of the present invention is to provide a assembly thatincludes a compliant contact with a lower self-inductance at higherfrequencies than existing technologies.

Another object is to provide a low-self-inductance contact assembly thatprovides sufficient compliance to test various UUT's.

Yet another object is to provide an assembly of low-self-inductancecontacts that can be made extremely small for testing UUT's with closeconduction points.

A further object is to provide a low-self-inductance contact assemblythat is relatively inexpensive to manufacture.

The present invention is an assembly that provides a temporary interfacebetween two electrical devices. The assembly is sandwiched between theelectrical devices and a compression force holds the combinationtogether. The assembly includes very low self-inductance, compliantcontacts. The contact includes a coil with a pair of opposed contactpoints for connection to conduction points on the electrical devices.The coil is at an angle to the direction of the compression. The smallerthe angle, the greater the force necessary to compress the contact.During compression, the coil loops are electrically shorted while theyslide along each other. The coil only needs to have enough of a loop tocause a short circuit between the leads when compressed, a minimum ofjust over 360°.

The material is any electrically conductive material which has inherentelastic properties and the cross-sectional shape of the material can beany shape, including round, square, triangular, elliptical, rectangular,or star, nor does the cross-sectional dimension have to be uniform overthe length of the material.

The contact points can each be configured in one of a variety ofconfigurations.

The contact is placed within a through aperture in a dielectric panel.The aperture has openings at both ends of a center section. The contactcan be captured within the aperture by a pin that extends through thecenter of the contact coil. Optionally, the remaining space of theaperture is filled with a compliant, electrically conductive elastomerthat adds resiliency and aids in electrically shorting the coil loops.

Other objects of the present invention will become apparent in light ofthe following drawings and detailed description of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

For a fuller understanding of the nature and object of the presentinvention, reference is made to the accompanying drawings, wherein:

FIG. 1 is a perspective view of the basic contact of the presentinvention with a coaxial lead;

FIG. 2 is a side view of the contact with oval loops;

FIG. 3 is a side view of the contact with parallel loop axes;

FIG. 4 is a cross-sectional view of the assembly of the presentinvention with a UUT and test bed;

FIG. 5 is a side view of the contact with varying gaps between loops;

FIG. 6 is a perspective view of the contact with a minimum coil;

FIG. 7 is a side view of the contact made from a rectangularcross-section material;

FIGS. 8A-8E are views in partial cross-section of the contact with acentered straight lead in an assembly;

FIGS. 9A and 9B are front and side views in partial cross-section of thecontact with an offset straight lead in an assembly;

FIGS. 10A and 10B are front and side views in partial cross-section ofthe contact with a skewed straight lead in an assembly;

FIGS. 11A and 11B are front and side views in partial cross-section ofthe contact with a hook lead in an assembly;

FIGS. 12A and 12B are front and side views of the contact with a hooklead and a tangent lead;

FIGS. 12C and 12D are top and bottom perspective views of the cap ofFIGS. 12A and 12B;

FIGS. 13A and 13B are front and side views of the contact with a nubcontact point;

FIGS. 14A and 14B are front and side views of the contact with analternate nub contact point in form of a tangent lead;

FIGS. 15A and 15B are front and side views of the contact with a loopcontact point;

FIGS. 16-21 are side views in cross-section of various contact captureconfigurations;

FIG. 22 is a bottom view in cross-section of a contact captureconfiguration;

FIG. 23 is a perspective view of the contact with a lead formed into aring; and

FIG. 24 is a perspective view of the contact with a lead tapered to apoint.

DETAILED DESCRIPTION OF THE INVENTION

The present invention is an assembly 11 that provides an interfacebetween two electrical devices, typically a unit under test (UUT) 2 anda test bed 4. The assembly 11 includes a compliant electrical contact 10with a very low self-inductance.

The contact 10 is created by winding or forming a length of electricallyconductive material into a coil 12. The coil 12 can be round, as in FIG.1, or oval, as in FIG. 2. The coil 12 can have a constant diameter orcan have a diameter that changes, such a conical shape. The loops 14 ofthe coil 12 may have a single axis 38, as in FIG. 1, or each loop 14 mayhave its own axis 38a-38e, all of which are parallel, as in FIG. 3. Thegap 44 between loops 14 of the coil 12, shown in FIG. 4, ranges fromessentially no gap (a closed coil) to a distance of up to about 100% ofthe largest wire cross-sectional dimension. The greater the wirecross-sectional dimension, the greater the gap 44 can be as a percentageof the cross-sectional dimension. For example, with a wirecross-sectional dimension of 0.0031 inch, a gap of 0.0001 inch (3%) isacceptable, whereas with a wire cross-sectional dimension of 0.020 inch,a gap of 0.010 inch (50%) is acceptable. The present invention alsocontemplates that different gaps 44 of the same coil 12 have differentsizes. For example, there may be no gap between some loops 14′ and gaps44 between other loops 14″, as shown in FIG. 5.

As described above and shown in FIG. 4, the contact provides a temporaryelectrical connection between the conduction points 6, 8 of a UUT 2 anda test bed 4. In order to provide a good electrical connection, thecontact 10 is compressed by application of a compression force 15 alonga direction of compression 17 between the UT 2 and test bed 4 so thatthe spring force of the contact 10 pushes the contact points 16, 18 ofthe contact 10 against the UUT conduction point 6 and the test bedconduction point 8.

The coil 12 is oriented such that the direction of compression 17 is atan angle 19 to the coil axis 38. When applying a compression force 15 inthe compression direction 17, the coil 12 provides compliance as theloops 14 slide along each other. When the compression force 15 isremoved, the loops 14 return to their quiescent condition. Whilecompressed, the coil 12 pushes the contact points 16, 18 against theconduction points 6, 8, providing an acceptable electrical connection.In addition, the coil 12 provides the necessary feature of adjusting forthe noncoplanarities of the conduction points 6, 8.

Once the gap 44 is closed, the loops 14 are electrically shortedthroughout the remaining compression of the contact 10 while they slidealong each other. The coil 12 only needs to have enough of a loop tocause a short circuit between the contact points 16, 18 when compressed,and thus can be extremely short with very low electrical parasitics. Thesmallest coil has slightly more than one loop, as shown in FIG. 6. Thematerial is coiled a minimum of just over 360° so that the ends of thecoil 12 make contact during compression.

The magnitude of the angle 19 depends on the particular application andthe compliance forces required for that application. The smaller theangle 19, the greater the force necessary to compress the contact 10,which means that the contact 10 will provide a greater force against theconduction points 6, 8. The magnitude of the angle 19 does have limits.As the angle 19 approaches zero, that is, parallel to the direction ofcompression 17, the contact 10 will not compress further once the coilshave come into contact with each other. And as the angle 19 passes 90°,that is, beyond perpendicular to the direction of compression 17, theloops 12 are less likely to contact each other to form a short circuitbetween the contact points. Consequently, the practical range for theangle 19 is from approximately 5° to approximately 90°.

In addition to the skew angle 19, the force versus deflection curve ofthe contact 10 is also determined by other coil parameters, such as thevolume of the material used in manufacturing the contact, e.g. the wirecross-sectional dimension, the coil diameter, and the number of loops,as well as the cross-sectional shape and material. The cross-sectionalshape of the material can be round, as shown in FIG. 1, or any othershape including square, as in FIG. 7, triangular, elliptical,rectangular, or star. The present invention also contemplates that thecross-sectional dimension does not have to be uniform over the length ofthe material. When using material with a cross-section having flatsides, such as rectangular or star-shaped, adjacent loops are in contactalong a greater surface area than when using material with a round oroval cross-section. Consequently, the shortest electrical path possibleis created, resulting in a lower inductance connection. However, forcost and other reasons, material with flat sides is not necessarilypreferred over round and oval material.

The material can be made of any electrically conductive material whichhas inherent elastic properties, for example, stainless steel, berylliumcopper, copper, brass, nickel-chromium alloy, and palladium-rare metalalloys, such as PALINEY 7®, an alloy of 35% palladium, 30% silver, 14%copper, 10% gold, 10% platinum, and 1% zinc. All of these materials canbe used in varying degrees of temper from annealed to fully hardened.

As indicated above, the contact 10 is used in an assembly 11 thatprovides temporary electrical connections to conduction points 6, 8between two electrical devices. In general, as shown in FIGS. 8A and 8B,the contact 10 is placed within a through aperture 24 in a dielectricpanel 26. The aperture 24 has openings 28 at both ends of a section 30through which the contact points 16, 18 protrude.

When a compression force 15 is applied in the compression direction 17to the contact points 16, 18 protruding through the openings 28 of thedielectric panel 26, the left side of the loops 14, as seen in FIG. 8A,compress and the right side of the loops expand, generally increasingthe diameter of the coil 12. The aperture 24 maintains the position ofthe contact 10 as the compression force 15 is applied. The aperture 24may also maintain the integrity of the contact 10 by preventing the coilloops 14 from separating under compression.

The contact 10 can be made extremely small by employing extremely smallwire and forming apertures 24 in the dielectric panel 26 for testingUUT's with pitches smaller than 0.5 mm (0.020″). The contacts 10 areadaptable to silicon wafer probing with pitches in the micrometers.

FIGS. 8A-22 show examples of a number of different contact point,aperture, dielectric panel, and contact capture configurations. Notethat both contact points 16, 18 of each figure are of the sameconfiguration. The present invention does not require that both contactpoints 16, 18 of a single contact be the same, but contemplates that thetwo contact points 16, 18 can have different configurations. Theconfigurations shown are merely examples and are not intended to limitthe present invention to any particular contact point, aperture, ordielectric panel configuration. Any contact point, aperture, and/orpanel configuration that works for a particular application iscontemplated by the present invention.

In FIGS. 8A-8E, the contact point 16 is at the end of a centeredstraight lead 72. The end of the coil 12 is bent through threedimensions, as at 74, to form the lead 72 that is generally aligned withthe direction of compression 17 and, when viewed from the contact point16, generally centered on the coil 12. The cross-sectional dimension ofthe center section 30 of the aperture 24 is slightly larger than thelargest dimension of the contact 10 perpendicular to the leads 72. Inthe configuration of FIG. 8C, the center section 30 has an oval crosssection, where the direction 40 in which the coil 12 expands has thelarger dimension. The smaller dimension 42 can be the same as the coildimension, since the coil 12 does not expand in that dimension 42. Theopenings 28 are generally coaxial with the center section 30 since theleads 72 are centered in the aperture 24. The aperture axis 58 of FIG.8A is aligned with the direction of compression 17. The openings 28 aresmaller than the coil 12 so that the contact 10 is captured by theaperture 24.

The dielectric panel 26 of FIG. 8A has a base sheet 34 that contains oneof the openings 28 and most of the center section 30, and a top sheet 32that contains the upper part of the center section and the other opening28. The contact 10 is placed in the base sheet part of the aperture 24and the sheets 32, 34 are sandwiched together, capturing the contact 10within the aperture 24.

An alternate arrangement of the contacts 10 within a dielectric panel 26is shown in FIG. 8D. Note that one contact point 16 extends farther fromthe coil 12 than the other contact point 18 and that the apertures 24are elongated and staggered. With this arrangement, the contacts 10 canbe placed closer together. Particular applications of this arrangementinclude 4-wire testing where each IC lead requires two contacts, one fora drive current and the other for high-impedance sensing.

Another alternate arrangement of the contact 10 within the dielectricpanel 26 is shown in FIG. 8E. The aperture axis 58 is slanted so thatthe leads 72 are aligned with each other, but not with the direction ofcompression 17. This arrangement allows for translation between thecontact point 16 and the electrical device conduction point 6. The panel26 is split so that the two parts of the aperture 24 are offset fromeach other.

In the configuration of FIGS. 9A and 9B, the contact point 16 is at theend of an offset straight lead 76 which is also aligned with thedirection of compression 17. The difference from the centered straightlead 72 is that, rather than being formed by a bend in three dimensionsand centered, the end of the coil 12 extends at a tangent to the loop 14and then bends in only two dimensions, so the lead 76 is at one side ofthe coil 12. Since the lead 76 is offset from the center of the contact10, the openings 28 are not coaxial with the center section 30, but areto one side.

FIG. 9A illustrates an advantage of the parallel lead 76: the contacts10 can be arranged very close together without having to elongate eitherof the leads 76, like with the coaxial lead 72 in FIG. 8D. Like thearrangement of FIG. 8D, particular applications of this arrangementinclude 4-wire testing where each IC lead requires two contacts, one fora drive current and the other for high-impedance sensing.

The dielectric panel 26 of FIG. 9A has two mirror image sheets 46, 48,where each sheet has one opening 28 and a half of the center section 30.The contact 10 is placed in one side of the aperture 24 and the sheets46, 48 are sandwiched together, capturing the contact 10 within theaperture 24.

In the configuration of FIGS. 10A and 10B, the contact point 16 is atthe end of a skewed straight lead 78 that is formed by ending the loop14 so that the lead 78 extends at a tangent to the loop 14. The resultis that the lead is not aligned with the direction of compression 17, ascan be seen in FIG. 10B. Because the lead 78 is tangent to the coil 12,it is perpendicular to the coil axis 38. The aperture openings 28 are tothe side of the center section 30, like those of the offset straightleads 76. However, because the skewed straight leads 78 are skewed fromthe direction of compression 17, the openings 28 may be elongated toallow for movement perpendicular to the direction of compression 17.

Optionally, as shown in FIGS. 10A and 10B, the space within the aperture24 remaining after the contact 10 is installed is filled with acompliant, electrically conductive elastomer 36. The elastomer 36performs a dual function. It adds to the resiliency of the contact 10,meaning that the contact 10 can tolerate more operational cycles thanwithout the elastomer 36. The elastomer 36 also aids in electricallyshorting the coil loops 14, thus potentially minimizing the electricalparasitic values of the contact system.

In the configuration of FIGS. 11A and 11B, the contact point 16 is theside 82 of a book lead 80. The end of the coil 12 extends tangentiallyfrom to coil 12 like the off set straight lead 76 of FIGS. 9A and 9B andthen is curved to form a hook 84 so that the contact point 16 is alongthe side 82 of the lead 80, rather than at the end 86 of the lead 80.The hook 84 can be any shape that provides the required function. Thehook 84 of FIG. 11A is formed of two bends 88 with a straight section 90therebetween. Alternatively, the book 84 may be a single bend of morethan 90°. The aperture openings 28 are slots that bisect the centersection 30 so that, when the hook 84 is compressed, it can flex into theslot.

In the configuration of FIGS. 12A and 12B, one contact point 16 is theupper surface 102 of a hook 100. The end of the coil 12 extendstangentially from the coil 12 and at an angle to the direction ofcompression 17 and then is curved to form a hook 100 so that the contactpoint 16 is along the side 102 of the hook 100, rather than at the endof the lead. The hook 100 can be any shape that provides the requiredfunction. The hook 100 of FIG. 12A is formed of as single bend of about90°. The other contact point 18 is the end of a lead 104 generallytangent to the coil 12 and at an angle to the direction of compression17, as shown in FIG. 12A. The lead 104 may be aligned with the coil in amanner similar to FIG. 10B or may be bent to more closely align with thedirection of compression 17, as in FIGS. 8 and 12B.

The contact 10 is placed in an open end 105 of the aperture 24 of thedielectric panel 26 such that the hook 100 extends through an apertureopening 28 at the other end of the aperture. The aperture opening 28 isintegral with the aperture 24 and is a slot that bisects the aperture 24so that, when the hook 100 is compressed, it can flex into the opening28. The open end 105 of the aperture 24 accepts a cap 106 that ispress-fit into the open end 105, as at 109. As shown in FIGS. 12C and12D, the cap 106 has an opening 107 through which the contact point 18extends. Inside the opening 107 is a slot 113 that the contact lead 104rides in, preventing the contact 10 from rotating during compression.The opening 107 can be the same shape as the slot 113, as seen in FIG.12D, or the opening 107 may be a different size, for example, smaller sothat only the contact point 18 extends from the opening 107.

The contact point 18 does not necessarily extend out from the opening107. The contact point 18 may extend through the opening 107 only enoughso that it lies generally in the plane of the lower surface 108 of thedielectric panel 26, and only enough to make contact with the UUTconduction point 6 or test bed conduction point 8 (depending upon thephysical arrangement of the items) during compression. Thisconfiguration is contemplated as an option for any of the contactconfigurations. The only limitation is that, if one of the contactpoints is generally in the plane of the dielectric panel surface, theother contact point must extend from the dielectric panel far enough sothe compression results in a good electrical connection between thecontact and the test bed and UUT.

In the configuration of FIGS. 13A and 13B, the contact point 16 is a nub92, which is the end of the coil 12 without any bends other than that ofthe loop 14. The nub 92 is aligned with the direction of compression 17.Alternatively, as shown in FIGS. 14A and 14B, the nub 92 is at the endof a very short lead 94 tangent to the coil 12, which may or may not bealigned with the direction of compression 17.

In the configuration of FIGS. 15A and 15B, the contact point 16 is theside 96 of a loop 14. It is essentially the same design as the nub 92 ofFIGS. 13A and 13B, but with the coil 12 rotated so that the side 96 of aloop 14, rather than the end 98 of the coil 12, is the contact point 16.If both contact points 16, 18 are on sides of loops 14, there must be atleast 1.5 loops 14.

Because the contact point configurations of FIG. 13A-15B do not haveleads that extend substantially from the coil 14 like the other contactpoint configurations, the aperture configurations with a central sectionand smaller openings do not necessarily provide optimum performance.FIGS. 16-22 illustrate aperture configurations more appropriate to thesecontact point configurations. These aperture configurations that capturethe contact 10 by means other than narrowed aperture openings can beused where appropriate for all of the contact configurations.

The aperture 24 of FIG. 16 has an axis 58 that is aligned with thedirection of compression 17, where the contact 10 is placed in thecenter section 30 with the contact points 16, 18 extending from theopenings 28. The contact 10 is held in place while a potting material 52cures to secure the contact 10 in the correct orientation. The pottingmaterial 52 can be conductive or nonconductive. The aperture 24 of FIG.17 has an axis 58 that is slanted from the direction of compression 17,where the angle of slant is substantially perpendicular to the angle ofthe coil axis 38. The contact 10 is secured in the center section 30 byeither a friction fit, that is, the aperture 24 is slightly smaller thanthe contact 10, or by a potting material like that of FIG. 16. Thecontact points 16, 18 extend from the openings 28.

FIGS. 18-22 show various methods of capturing the contact where a pin ofsome form extends through the center of the coil 12.

The aperture 24 of FIG. 18 is slanted from the direction of compression17, where the angle of the slant is essentially perpendicular to theangle of the coil axis 38. The pin that secures the contact 10 is a rod54 that extends through holes 56 in the dielectric panel 26 and thecenter of the coil 12. The contact points 16, 18 extend from theopenings 28.

In FIG. 19, the pin is a protrusion 110 extending from the wall of acenter section 30 of the aperture 24 that is slanted to the direction ofcompression 17. The protrusion 110 extends into the coil 12 to securethe contact 10 in the aperture 24. A second protrusion 111 is optional.In FIG. 20, the pin is a pair of coaxial protrusions 112 extending fromthe walls of a center section 30 of the aperture 24 that is slanted tothe direction of compression 17. The dielectric panel 26 separateshorizontally at an interface 116 that bisects the aperture 24. Thecontact 10 is installed in one side of the aperture 24 and then the twopanel components 118, 120 are assembled horizontally so that theprotrusions both extend into the contact 10.

The pin of FIG. 21 is also a protrusion 122 extending from the wall ofthe center section 30. After the contact 10 is installed, a plug 126 isinstalled in the aperture 24 that secures the contact 10 in theaperture. Optionally, there is a protrusion 124 on the plug 126.

In FIG. 22, the contact 10 is placed in the aperture 24. The pin thatsecures the contact 10 in the aperture 24 is an elastic band 60 thatextends through holes 62 in the dielectric panel 26 and the center ofthe coil 12. The band 60 can extend through more than one contact 10.Because the band 60 is elastic, the contacts 10 do not have to bealigned so that the hole 62 runs in a straight line, but can curvearound corners. The band 60 is composed of an insulating material, suchas a silicon rubber.

The contact points 16, 18 can be configured in shapes that aid incontact integrity. One example of a contact point formation is ahemisphere or ring 20, shown in FIG. 23, for receiving a ball contact asin the testing of a ball grid array (BGA) device. Another example is aspear, shown in FIG. 24, with one or more prongs 22 for piercing oxidesat the conduction point 6, 8.

Thus it has been shown and described a compliant electrical contactassembly which satisfies the objects set forth above.

Since certain changes may be made in the present disclosure withoutdeparting from the scope of the present invention, it is intended thatall matter described in the foregoing specification and shown in theaccompanying drawings be interpreted as illustrative and not in alimiting sense.

1. A compliant electrical contact assembly adapted to provide atemporary electrical connection between a conduction point of a firstelectrical device and a conduction point of a second electrical device,said electrical devices being compressed together by a compression forcein a direction of compression with said assembly therebetween, saidassembly comprising: (a) at least one compliant electrical contact, saidcontact including a length of an electrically conductive, inherentlyelastic material, said material being formed into a coil having at leastslightly more than one loop, each loop having an axis, said loop axesbeing at a first angle from said direction of compression, and saidcontact having generally opposed contact points for electricalconnection with said conduction points, one of said contact points beingon a lead that is generally tangent to said coil and at a second angleto said direction of compression, the other of said contact points beingon a hook-shaped lead ; and (b) a dielectric panel having a throughaperture for each of said at least one electrical contact, said contactbeing captured in said aperture such that said contact points extendthrough opposed openings of said aperture.
 2. The compliant electricalcontact assembly of claim 1 wherein said loop axes are coaxial.
 3. Thecompliant electrical contact assembly of claim 1 wherein said firstangle is in the range of from approximately 5 degrees to approximately90 degrees.
 4. The compliant electrical contact assembly of claim 1wherein a first of said opposed openings is a slot integral with saidaperture and through which said hook-shaped lead extends, and a secondof said opposed openings is within a cap that fits within an open end ofsaid aperture opposite said slot.
 5. The compliant electrical contactassembly of claim 1 wherein said cap is press-fit into said open end. 6.A compliant electrical contact assembly adapted to provide a temporaryelectrical connection between a conduction point of a first electricaldevice and a conduction point of a second electrical device, saidelectrical devices being compressed together by a compression force in adirection of compression with said assembly therebetween, said assemblycomprising: (a) at least one compliant electrical contact, said contactincluding a length of an electrically conductive, inherently elasticmaterial, said material being formed into a coil having at leastslightly more than one loop, each loop having an axis, said loop axesbeing at an angle from said direction of compression, and said contacthaving generally opposed contact points for electrical connection withsaid conduction points; and (b) a dielectric panel having a throughaperture with an axis for each of said at least one electrical contact,said contact being captured in said aperture by a pin extending throughsaid coil.
 7. The compliant electrical contact assembly of claim 6wherein said loop axes are coaxial.
 8. The compliant electrical contactassembly of claim 6 wherein said angle is in the range of fromapproximately 5 degrees to approximately 90 degrees.
 9. The compliantelectrical contact assembly of claim 1 wherein the other of said contactpoints is on a side of said coil generally opposite said lead.
 10. Acompliant electrical contact assembly adapted to provide a temporaryelectrical connection between a conduction point of a first electricaldevice and a conduction point of a second electrical device, saidelectrical devices being compressed together by a compression force in adirection of compression with said assembly therebetween, said assemblycomprising: (a) at least one compliant electrical contact, said contactincluding a length of an electrically conductive, inherently elasticmaterial, said material being formed into a coil having at leastslightly more than one loop, said coil having an axis at a first anglein the range of from approximately 5 degrees to approximately 90 degreesfrom said direction of compression, and said contact having generallyopposed contact points for electrical connection with said conductionpoints, one of said contact points being on a lead that is generallytangent to said coil and at a second angle to said direction ofcompression, and the other of said contact points being on a side ofsaid coil generally opposite said lead; and (b) a dielectric panelhaving a through aperture for each of said at least one electricalcontact, said contact being captured in said aperture such that saidcontact points extend through opposed openings of said aperture.
 11. Acompliant electrical contact assembly adapted to provide a temporaryelectrical connection between a conduction point of a first electricaldevice and a conduction point of a second electrical device, saidelectrical devices being compressed together by a compression force in adirection of compression with said assembly therebetween, said assemblycomprising: (a) at least one compliant electrical contact, said contactincluding a length of an electrically conductive, inherently elasticmaterial, said material being formed into a coil having at leastslightly more than one loop, said coil having an axis at a first anglein the range of from approximately 5 degrees to approximately 90 degreesfrom said direction of compression, and said contact having generallyopposed contact points for electrical connection with said conductionpoints, one of said contact points being on a side of said coil; and (b)a dielectric panel having a through aperture for each of said at leastone electrical contact, said contact being captured in said aperturesuch that said contact points extend through opposed openings of saidaperture.
 12. The compliant electrical contact assembly of claim 11wherein said loop axes are coaxial.
 13. The compliant electrical contactassembly of claim 11 wherein said first angle is in the range of fromapproximately 5 degrees to approximately 90 degrees.